Last October the U.S. government ruled under the DMCA that software unlocking your cell phone is illegal. The law will take effect on the 27th of january (this Sunday) when the three month window closes. This kind of government intervention is a burden to consumers and further states that you do not fully own the products you are buying. This being said, factory unlocking your phone using an imei will still remain legal this only restricts tools like ultrasn0w that unlock the iPhone for free via a software exploit.
While we don’t know how well the law will be enforced, I doubt we will see any developers create software unlocks as they will be clearly breaking the law and possibly be liable for the people that uses them. While the law is not fully ridiculous like the jailbreak ban on iPads it surly angers many people. Bye bye freedom!